"I don't think you mean to imply that Leonard was laying down
hard and fast rules that all others must follow, . . ."

No, I did not mean to imply that.

". . . but, just so it's clear, I think what Leonard actually
said was,
"I try to leave out the parts most people skip.""

That's how he summed up his rules. However, Leonard laid down
some very specific rules about what typified those "the part
that readers tend to skip." -- detailed descriptions of
weather, place, things, characters, etc.

"In other words, he was setting a personal rule that worked
for him, not a universal rule that he insisted would work for
all."

True. I don't get the impression that he was trying to tell
James Lee Burke he should change his entire style.

However, given that he wrote up his rules for the New York
Times, and that he called them rules, I'm sure many have
followed them. And the Post's Anderson is far from the only
critic I've read who invokes the rules while judging other
writers. (Of course, Anderson forgets all about the rules
when he likes a book, like Izzo's, that doesn't bide by
them.)